We investigate the brine-rich side (volume fraction of brine >0.8) of the phase diagram of a quasi-ternary system: Cetylpyridinium chloride/hexanol/brine (0.2 M NaCI). The three classical phases LI, lamellar, and L2 appear on this side of the diagram. Their respective stabilities are mainly determined by the alcohol-to-surfactant ratio in the solution and only slightly depend on the dilution. We try to understand the phase behavior in terms of morphological transformations of the elementary objects (micelles, bilayers) induced by the variations of the alcohol/surfactant ratio. The analysis is based on the idea that adding alcohol induces a monotonic variation of the spontaneous curvature of the surfactant film. The simple model proposed by McMullen et al. (McMuIlen, E. W., Ben-Shaul, A.; Gelbart, W. M. J. Colloid Interface Sci. 1984, 98, 523)is used in order to investigate the morphology sequence which arises from this simple analysis: spheres, small disks, long capped cylinders, branched cylinders, bilayers perforated by a large density of pores, smooth bilayers, loose network of connected bilayers (foamlike structure). This shape sequence agrees (at least qualitatively) with the phase behavior of the system. And also, the model is able to reproduce adequately several otherwise reported phenomena, which are the second cmc at the "sphere to rod" transition in binary mixtures, the LI/LI phase separation in dilute binary mixtures of ionic surfactants, and the formation of lamellar phases perforated by "structural defects".

We also investigated the dependence of the substrate semiconductor on the electron transfer using 2 and 3 on Ti02 and Sn02. The results are summarized in Table IV. k[t for 2 and 3-Ti02 is slightly larger than that for the chemically modified system.If we compare the characteristics of electron transfer to Ti02 with that to Sn02, k[t are comparable, while the ratio of fast-decay component for Sn02 is clearly larger than that for Ti02. This leads to the conclusion that the difference of electron-transfer efficiencies between Sn02 and Ti02 is determined mainly by the ratio of adsorbed molecules having a strong electron-transfer interaction with semiconductor surfaces to those having a weak electron-transfer interaction with semiconductor surfaces to those having a weak electron-transfer interaction. This point is quite different from the electron transfer from adsorbed Ru(II) complexes to semiconductors in vacuo, in which the electron-transfer rate is strongly dependent on the semiconductor material.31 ConclusionLuminescence decays of Ru(bpy)32+ derivatives immobilized on Ti02 powder in various solvents could be fitted by the sum of (31) Hashimoto, K.; Hiramoto, M.; Sakata, T., manuscript in preparation. (32) r, was also determined separately from the decay curve measured longer time scale, so that its error is relatively small. The error limit of t; was usually less than 20%. However, it became larger when the relative weight of the fast component decreased, but did not exceed 30%. two exponentials. It could be determined that the lifetime of fast-decay component was determined mainly by the electron transfer from the excited state of the Ru(II) complexes to semiconductor. The rate constants and the quantum efficiency of the electron transfer were obtained by comparing the decay curves on semiconductor to those on insulator. The variation in quantum efficiency of the electron transfer with solvent is mainly due to the ratio of the preexponential factors of fastand slow-decay components, indicating that there are extreme configurations for the immobilized complexes on Ti02 in most solvents, and the ratio of molecule numbers of each form depends on the solvent.

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